"Each of two or more forms of the same element that contain equal numbers of protons but different numbers of neutrons in their nuclei" and is radioactive is
A. An isotope
B. A radioisotope
C. A nuclide
D. A radionuclide
E. None of the above

There is no reason to think the results are biased or not conducted properly but you should not assume the results are correct just because they were done in a laboratory so the answer would be c. it is likely to be reliable because the results support the conclusion presented.

Idon’t know what the answer is i wish i could